JP3529768B2 - Electrostatic actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic actuator driven by electrostatic force, and more particularly to a method of fixing an electrode substrate to a stator.

[0002]

2. Description of the Related Art Since electrostatic actuators are small and lightweight, they are used in endoscopes, mobile phones such as mobile phones, and various PDAs.
It can be used for focusing of a lens mounted on a camera, etc., and has recently been receiving attention. FIG. 3 is a perspective view showing an example of such an electrostatic actuator.

The electrostatic actuator 100 includes a stator 11
0, and a mover 120 which is guided by the stator 110 and is capable of reciprocating in a predetermined direction and having an electrode surface 121 formed on a pair of surfaces facing each other. Further, the stator 110 includes an electrode substrate 111 that drives the mover 120 by applying an electrostatic force, and a fixed frame 112 that fixes the electrode substrate 111. A pattern 111a for generating an electrostatic force is formed between the electrode substrate 111 and the mover, and the pattern 111a is a drive circuit (not shown).
It is connected to the. On the other hand, the mover 120 has a lens group 1
22 is held.

The surface of the electrode substrate 111 of the electrostatic actuator 100 and the electrode surface 121 of the mover 120 are formed with a gap of several μm, and are moved by applying a voltage to the pattern 111a in a drive pattern according to the drive direction. The child is driven.

In the electrostatic actuator having the structure as described above, as a method of assembling the electrode in the fixed frame, the fixed frame is manufactured in advance, and then the electrode is bonded and the electrode is integrally molded by resin molding. There are ways.

[0006]

The method of attaching the electrode substrate in the above electrostatic actuator has the following problems. That is, in the method of integrally molding the electrode substrate and the fixing frame that fixes the electrode substrate, the difference in material, for example, when the electrode substrate made of a silicon material and the fixing frame made of a thermoplastic resin material are filled with resin. Strain may occur on the electrode substrate surface after molding due to the influence of molding pressure, resin shrinkage during molding, difference in linear expansion coefficient, and the like. Therefore, it is difficult to form the above-mentioned gap with an accuracy of several μm. Further, in the stator frame in which the electrodes are formed by adhesion, there is a problem that the electrode substrate is deformed due to the change in environmental temperature due to the difference in linear expansion coefficient between the electrodes and the fixed frame.

On the other hand, in the electrostatic actuator, as a means for supplying electric power from the drive circuit to the electrode substrate, it is necessary to incorporate a power supply terminal from the fixed frame by a method such as FPC wiring from the electrode surface. Therefore, it is necessary to secure a gap through which the FPC wiring passes, and there is a certain limit to miniaturization.

[0008] Therefore, an object of the present invention is to provide an electrostatic actuator which can always exhibit a stable driving force and can be miniaturized.

[0009]

In order to solve the above problems and achieve the object, the electrostatic actuator of the present invention is constructed as follows.

(1) In an electrostatic actuator having a stator and a mover guided by the stator and capable of reciprocating in a predetermined direction and having electrodes formed on a pair of opposing surfaces, The stator is a resin-made stator frame, an electrode substrate attached to the stator frame, and the stator frame.
A holder disposed at one end side of the electrode substrate and a fixing member for fixing to the stator frame, said fixing member
Is attached to the stator frame and elastic force
Mounted on the holder and the first pin member that fixes the electrode substrate.
It is attached and fixes the electrode substrate by elastic force
And a second pin member .

(2) In the electrostatic actuator described in (1) above, the fixing member is a power supply pin that supplies power to the electrode substrate from the outside.

(3) In the electrostatic actuator described in (1) above, the mover, the stator frame, and the base have substantially the same linear expansion coefficient.

(4) The electrostatic actuator described in (1) above, wherein the mover supports a lens.

[0014]

1 is an exploded perspective view showing an electrostatic actuator 10 according to an embodiment of the present invention, FIG. 2 is a view showing the electrostatic actuator 10, and FIG. (B) is a longitudinal sectional view. Note that arrows XYZ in these figures indicate three directions orthogonal to each other.

The electrostatic actuator 10 includes a stator 20.
And a movable element 80 which is guided by the stator 20 and is capable of reciprocating along the arrow X direction.

The stator 20 includes a holder 30 and a stator frame 4
0 and the pair of electrode substrates 5 supported by the stator frame 40
It has 0 and 50. 1 and 2, reference numeral 60 denotes an electrode fixing pin (fixing member), and 70 denotes a power supply pin (fixing member).

The holder 30 has a holder body 31 formed of a resin material in a rectangular parallelepiped shape. Recesses 32 and 33 are formed in the holder body 31, and the bottoms of the recesses 32 and 33 are communicated with each other through a through hole 34. The inner diameter of the concave portion 32 is formed to have a size that fits the outer periphery of the stator frame 40. On the other hand, the recess 33 has a CCD
The sensor 35 is attached, and the light receiving surface 35 a thereof is exposed to the recess 32 side through the through hole 34.

The holder body 31 is integrally formed with a plurality of power supply pins 70 (eight in the figure), and the tip thereof is bent. The power supply pin 70 is connected to an external drive circuit (not shown).

The stator frame 40 is made of a rectangular frame-shaped resin material, and has a pair of electrode supporting portions 41 and 42 facing each other.
It is provided with a pair of wall portions 43 and 44 facing each other and a bottom wall portion 45. The electrode support portions 41, 42 include engagement portions 41a, 42 for restricting movement of the electrode substrate 50 in the arrow Y direction.
a is formed. Further, the wall portions 43 and 44 are respectively formed with two cutout portions 43a and 44a. Four electrode fixing pins 60 are attached to the notches 43a and 44a. The electrode fixing pin 60 is formed of a leaf spring and is molded integrally with the stator frame 40.

The electrode substrate 50 is formed of a glass substrate 51, and an electrode pattern 52 is formed on the glass substrate 51.
Are formed. The electrode pattern 52 faces upper and lower electrode surfaces 82 of a mover 80, which will be described later. Electrode pattern 52
Is provided with electrodes composed of a plurality of systems formed along the moving direction of the mover 80. Further, these electrodes are connected to the connection pad 53.

The mover 80 is a square tube-shaped mover body 81.
Is equipped with. On the pair of opposing electrode surfaces 82 of the mover body 81, convex stripe electrodes are formed by fine processing. A lens group 83 is supported by the mover body 81.

The holder body 31, the stator frame 40, and the mover body 81 are preferably made of a resin material having substantially the same linear expansion coefficient.

The electrostatic actuator 10 as described above is assembled as follows. First, the electrode substrate 50 is inserted into the stator frame 40. At this time, the surface of the electrode substrate 50 contacts the electrode fixing pin 60, and the electrode fixing pin 60 bends. The electrode substrate 50 is positioned when the electrode substrate 50 contacts the bottom wall portion 45. At the same time, the electrode fixing pin 60
The electrode substrate 50 is fixed to the stator frame 40 by the elastic force of.

Next, the stator frame 40 is inserted into the holder 30 while bending the power supply pin 70. At this time, the outer periphery of the stator frame 40 fits into the recess 33 of the holder 30, as described above. At this time, the power supply pin 7
The tip of 0 abuts on the connection pad 53 of the electrode substrate 50 and becomes conductive. At the same time, the elastic force of the power supply pin 70 fixes the electrode substrate 50 to the stator frame 40.

As described above, in the electrostatic actuator 10 according to the present embodiment, the electrode substrate 50 is fixed to the stator frame 40 by using the electrode fixing pin 60 and the power supply pin 70. Therefore, it is possible to prevent the distortion of the electrode substrate 50 which is generated by the method of integrally molding the electrode substrate 50 and the stator frame 40. Further, the stator frame 40 and the electrode substrate 50 are not integrated with an adhesive. Therefore, although there is a difference in linear expansion coefficient between the stator frame 40 and the electrode substrate 50, the electrode substrate
Since 0 slides with respect to the stator frame 40, the electrode substrate 50 does not warp. Therefore, the electrode substrate 5
The gap variation between 0 and the mover 80 can be minimized. Therefore, a stable driving force can always be exhibited.

Further, since the power supply pin 70 can be used as a means for supplying electric power from the drive circuit, it is not necessary to use FPC wiring or the like. Therefore, FP
Since it is not necessary to secure a gap for routing the C wiring, the entire structure can be downsized. Further, since the electric power can be supplied only by fitting the stator frame 40 to the holder 30, the assembly process can be simplified and the manufacturing cost can be reduced.

Further, the holder body 31, the stator frame 40,
Since the mover main body 81 is made of a resin material having a substantially equal linear expansion coefficient, it is possible to minimize the occurrence of strain due to temperature change.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0029]

According to the present invention, a stable driving force can be constantly exerted and the size can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an electrostatic actuator according to an embodiment of the present invention.

FIG. 2 is a view showing the electrostatic actuator,
(A) is a front view and (b) is a longitudinal sectional view.

FIG. 3 is a perspective view showing an example of a conventional electrostatic actuator.

[Explanation of symbols]

10 ... Electrostatic actuator 20 ... Stator 30 ... Holder 40 ... Stator frame 50 ... Electrode substrate 60 ... Electrode fixing pin (fixing member) 70 ... Power supply pin (fixing member) 80 ... mover

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02N 1/00 H02N 11/00 G02B 7/04 G02B 7/08

Claims (4)

(57) [Claims] 1. An electrostatic actuator comprising: a stator; and a mover guided by the stator to reciprocate in a predetermined direction and having electrodes formed on a pair of opposing surfaces. The stator includes a resin-made stator frame, an electrode substrate attached to the stator frame, and one end side of the stator frame.
A location has been the holder, the electrode substrate and a fixing member for fixing to the stator frame, said fixing member, when attached to the stator frame DOO
A first pin member for fixing the electrode substrate by elastic force,
The electrode is attached to the holder by elastic force.
A second pin member for fixing the substrate,
An electrostatic actuator. 2. The electrostatic actuator according to claim 1, wherein the fixing member is a power supply pin that supplies power to the electrode substrate from the outside. 3. The electrostatic actuator according to claim 1, wherein the mover, the stator frame, and the base have substantially the same linear expansion coefficient. 4. The electrostatic actuator according to claim 1, wherein the mover supports a lens.